The present invention relates to a mount component such as a cable clamp which is used to mount an electronic component, a cable, or the like on a board of an electronic device or the like and, more particularly, to a snap structure for attaching a mount component on a board.
When assembling an electronic device, electronic components must be attached to an assembly board such as a panel, chassis, board, or the like (which will be referred to as a board hereinafter), and a coiring component such as a cable must be extended on the board. A mount component is used for this purpose. For example, when a cable is to be extended along the surface of a board, a cable clamp which holds a cable and attaches it to a chassis is used. Generally, a snap structure is employed as a structure for attaching a cable clamp to a chassis. FIG. 17 shows an example of the snap structure. A cable clamp 1D is constituted by a clamp portion 60 for holding a plurality of cables C in the form of a bundle, and a snap portion 30A formed integrally with the clamp portion 60 and to be fitted in a through hole 3 formed in a board 2. The cable clamp 1D is monolithically formed by resin molding or the like. In the clamp portion 60, a cover piece 62 is coupled at its one end to an upward U-shaped base 61 with a hinge, and its other end is locked by a locking portion 63. The cables C can be inserted or removed by opening or closing the cover piece 62. The snap portion 30A has a pair of snap pieces 52 extending like arrowheads on the two sides of a post 31 which projects downward. When the snap portion 30A is inserted in a through hole 3 from the upper surface of the board 2, the pair of snap pieces 52 are elastically reduced in diameter so they are inserted in the through hole 3. After passing through the through hole 3, the snap pieces 52 are elastically restored and enlarged in diameter, so that steps 521 formed at the distal ends of the snap pieces 52 engage with the inner edge of the through hole 3. A pair of leg pieces 34 which form an inverted V shape and oppose the snap pieces 52 abut against the upper surface of the board 2, so that engagement of the steps 521 and through hole 3 is held. This prevents the cable clamp 1D attached to the board 2 from disengaging from the through hole 3.
In recent years, regarding home electrical appliances, OA devices, automobiles, and electronic devices as a whole, the sale of environment-friendly products is obliged as a solution to the environmental issues. Along with this demand, for example, a printed board or wiring lines built in an electronic device must be able to be disassembled from the chassis, panel, or the like of the electronic device. Particularly, to facilitate the disassembling operation, the printed board or wiring lines must be disassembled easily without using any tools. For this reason, in assembly of an electronic device, a mount component of this type must be able to be attached to a through hole of a board easily. In disassembly of the electronic device, the mount component must be able to be removed easily from the through hole manually. A snap portion 30B shown in FIG. 18A as an example of such a snap structure is described in Japanese Patent Laid-Open No. 2001-278329 and is applied to a cable tie (to be described later). Arrowhead-shaped snap pieces 52 are formed on the two sides of the distal end of a straight plate-like post 51. The snap pieces 52 and connecting pieces 53 connected to the distal ends of the snap pieces 52 form steps 521. The connecting pieces 53 respectively integrally have disengaging pieces 55 that are directed outwardly and can be held with fingers. Leg pieces 54 project in the two sides from the disengaging pieces 55. In this snap structure, to disassemble from a through hole 3 the snap portion 30B fitted in the through hole 3, the disengaging pieces 55 are held with fingers from the two sides and are deformed inwardly, as indicated by alternate long and two short dashed lines in FIG. 18A. Interlocked with this, the snap pieces 52 reduced in diameter. The snap structure facilitates this reduction in diameter, and the snap pieces 52 can be easily disengaged from the through hole 3. This is effective as a solution to the environmental issues.
With this snap structure, if the disengaging pieces 55 and leg pieces 54 are designed to have a large elastic force, when the snap portion 30B is to be disengaged from the through hole 3, the force of the fingers to be applied to the disengaging pieces 55 can be reduced. However, the inward force increases due to the elastic force of the disengaging pieces 55 and leg pieces 54. Accordingly, the snap pieces 52 are biased in the diameter reducing direction, and the fitting force with respect to the through hole 3 decreases undesirably. If the disengaging pieces 55 and leg pieces 54 are designed to have a small elastic force, the support force of the leg pieces 54 decreases, and the post 51 can be inclined easily by an external force or the like. When the inclination of the post 51 becomes large as in FIG. 18B, one snap piece 52 deforms toward the post 51, and the other snap piece 52 moves into the open edge of the through hole 3 and disengages from the through hole 3. Then, the snap portion 30B undesirably drops from the through hole 3. As a result, the fitting force of the snap pieces is decreased by the diameter reduction of the snap pieces, making it difficult to obtain a stable, highly-reliable snap structure. This problem occurs not only in a cable clamp but also applies to all mount components that have similar snap structures.
It is an object of the present invention to provide a snap structure which allows a mount component to be attached to or removed from a board easily while preventing the mount component from undesirably disengaging from the board.
In order to achieve the above object, according to the present invention, there is provided a snap structure comprising a post, arrowhead-shaped snap pieces formed at a distal end of the post and elastically deformable in a radial direction, leg pieces arranged to oppose the snap pieces, and disengaging pieces which are connected each to one end of corresponding one of the snap pieces that are enlarged in diameter and which are capable of reducing in diameter the snap pieces manually, the snap pieces serving to deform elastically in the radial direction, upon insertion in a through hole formed in a chassis, to be fitted in the through hole, so as to clamp the chassis together with the leg pieces, wherein the post comprises a stopper portion for prohibiting the post from being inclined in the through hole at not less than a predetermined angle.